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<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var obj = {
            name: "张三",
            age: 15,
            tel: 110
        }

        var arr = [1, 2, 3, 4]
        // for(let key in obj) {
        //     console.log(key)
        // }
        var set = new Set(arr)
        console.log(set)

        // for...of可以循环数组 伪数组和类数组对象还有字符串
        for(let value of set) {
            console.log(value)
        }
    </script>
</body>
</html>